THE HORSE. Temporary Incisors. The tem porary incisors, being mere shells just at the time of eruption of the permanent teeth, are easily removed by a human molar tooth forceps. They are often removed by horse-dealers at an earlier period to hasten the eruption of the per manent teeth and make the horse appear a year older than the true age. An awl is com monly employed by them to prise out the teeth.
Temporary Molars. Control as for section of the teeth. The gag, which is applied between the upper and lower rows of molars on one side, is suitable for this operation, the one made of wood for preference. A fairly stout forceps, about fifteen inches long, with short corrugated jaws at right angles to its long axis is suitable. It can be used with one hand. The temporary crown is distinguished from the permanent one by the former having a worn surface with sharp borders and being shell-like on percussion; while the latter, not having undergone wear, has rounded borders and is solid on percussion. Having grasped the tooth with the forceps it is easily wrenched off.
Permanent Molars—Control. If the tooth to be removed is not firmly fixed and the animal is quiet it can be extracted in the standing position, the horse being controlled as for pre ceding dental operations. Stocks are very convenient for the purpose. If the tooth is firmly embedded, especially in a young horse in which the fang is long, or if the subject be diffi cult to handle, it is better to cast and anesthetize the patient, having him lying on his side with the head turned so as to rest on its poll, and having the light as far as possible shining into the mouth. A torch or mirror may be used to illuminate the oral cavity.
Instruments. The forceps used for extracting the permanent molars requires to be a powerful instrument made of the best steel, its handles being about two feet long and half an inch in circumference. Its jaws are bent at right angles to the handle and are coarsely dentic ulated to grip the teeth, to which they are firmly fixed by means of a screw, which brings the handles together. The teeth being extracted from their sockets by leverage applied parallel to their long axis, and the fangs of the anterior molars being directed upwards and slightly forwards (the head being horizontal), and those of the posterior molars having the - opposite direction, a lever of the first order would be required for the posterior teeth and one of the second order for the anterior ones. Hence a forceps with a prominent prolongation at the free extremity of its jaws to act as a fulcrum is suitable for the anterior molars, and one with a prominence on the joint of the instrument, for the same purpose, is convenient for the posterior molars. For the latter teeth a plate of wood or metal attached to a handle can be placed on the teeth immediately in front of the one grasped by the forceps to serve as a fulcrum, the instrument itself, in this case, not being provided with a fulcrum. Gunther has invented forceps answering the above requirements. The one for the anterior molars has its two branches jointed at one end like a compass, with its jaws a little distance from this extremity so that the latter serves as a fulcrum. The one for the posterior molars has its jaws at the ex tremity of the instrument and the joint at the base of the jaws. A separate instrument is used as a fulcrum in this case.
Operation. Insert the oral speculum and have the tongue held out of the mouth as usual. Make sure of grasping the right tooth. If possible, place a finger on the tooth just beyond the one to be removed and introduce the forceps up to the finger. Have the mouth illuminqted by natural or artificial light to enable you to see clearly what you are doing. The mistake of removing the wrong tooth has occurred often enough. Grasp the tooth as close to the fang
as possible; fix the jaws of the forceps by turning the screw on the handles, avoiding great pressure if the tooth is hollow from caries for fear of crushing it; loosen the tooth by restricted side to side movements, tending to rotate the tooth on its long axis and by see-saw movements of the cross-bar on the handles. Having loosened the tooth, introduce the ful crum beneath the forceps as near as possible to the jaws if a lever of the first order is being used, and prise out the tooth. If the fang be long it may be necessary to take a second grip with the forceps. In many cases in old subjects in which the fangs of the teeth are short they can be removed without the aid of a fulcrum, as they come away easily once they are made loose. One hand beneath the instrument is often sufficient as a point d'appui.
Having extracted the tooth, little after-treat ment is required as a rule. The mouth should be washed out with a suitable lotion such as potassium permanganate solution, and this should be repeated after meals until the alveolus is nearly healed. If there be a large dental fistula opening on the skin, introduce a plug of gauze through the external orifice and keep the outer portion of the passage occluded until the lower portion is nearly obliterated by granu lation tissue, the object being to prevent the . escape of alimentary matter, which would delay the healing process. If there be pus or food material in the sinus, the latter must be evacuated and treated as described.
Permanent Incisors. The permanent incisors rarely require extraction except they have become very loose as the result of an accident and there is no possibility of their becoming fixed again. They are then easily removed. A forceps of the same pattern as human dental forceps, but proportionately larger, answers the purpose.
THE DoG. Temporary Teeth. The tem porary incisors and canines often persist after development of the permanent teeth, which are situated immediately behind them. They are a source of discomfort. Remove them with a small human tooth forceps, grasping the tooth as close as possible to the gum and using a cautious rotary movement to loosen the tooth without breaking it. When they do break at the level of the gum, no bad effects result from the embedded fangs.
Permanent Incisors or Molars. When the per manent molars or incisors are affected with alveolar periostitis they are more or less loose and are very easily extracted. Apart from this disease the incisors rarely require removal. The fourth upper molar or earnassial tooth must be removed in a case of dental fistula due to pus in the antrum. For the operation, have the dog securely held or fixed in the ventral position on the table. Chloroform anesthesia is seldom necessary, but if the animal offer great resistance a hypodermic injection of morphia may be used to keep the patient quiet. Have the mouth widely opened by means of a speculum or tapes on the upper and lower jaws. Grasp the tooth firmly above the crown with the molar tooth forceps, and with vigorous but restricted side to side and rotary movements loosen the tooth and then remove it by a strong pull parallel to the long axis of its fangs.
4. Repulsion of Teeth. Indications. Repul sion of teeth is indicated in eases where the teeth require to be removed and the forceps cannot be used for the purpose owing to the crowns being absent or being too small to afford a grip for the instrument, or because there are odonto mata on their fangs preventing their with drawal without fracture of the jaw.